From: gdpusch@NO.xnet.SPAM.com (Gordon D. Pusch)
Newsgroups: sci.physics.plasma
Subject: Re: Gas Gun Fusion?
Organization: XNet Information Systems, Inc.
References: <bggaou$7l8s$1@saturn.cs.uml.edu>


steve_ivy@dlbweb.com (Fusion Dude) writes:

> Take two hyper-velocity light gas guns. (The kind that guy used to
> create metallic hydrogen a few years ago.)

Way too low a velocity, by at =LEAST= an order of magnitude (see below).


> Aim their barrels right at each other (co-axially)
>
> Fire the guns into the two open ends of a very powerful magnetic
> solenoid.
>
> The fuel/projectiles will be something like lithium deuteride with
> neutron moderator layers across their bases and around the sides.

"Moderators" are for _FISSION_, not fusion! What you want is a neutron
_REFLECTOR_ to impede the escape of the neutrons that are breeding
tritium from the lithium, and backed up by a massive high-Z "tamper"
material to inertially confine the "burn." Better yet, skip attempts
at "in situ breeding," and just use tamper-surrounded D/T as the projectile.


> Basically a modified Teller Ulam structure in miniature with open front
> faces for the lithium deuteride to meet.
>
> These "bullets" will slam right into each other right in the center of
> the solenoid.
>
> So could a design like this get you fusion conditions?

A number of authors (most notably Friedwardt Winterberg) have extensively
investigated such "impact driven fusion," including the "magnetized target"
impact driven fusion variant. Minimum estimates for the relative collision
velocity required is on the order of 50 to 100 km/sec --- well beyond the
capabilities of even a multi-stage gas gun. Electromagnetic macroparticle
accelerators _might_ be able to reach such velocities, but size estimates
for such devices are in the 10 to 100 of kilometer range, and make even
the Superconducting Super-Collider look cheap !!!


> If not then you might "sweeten" the design with a little fission fuel but
> I would really prefer not to do that for obvious reasons.

More to the point, it won't work.


> You also might want to use deuterium or tritium
> as the final stage (pusher) gas in the light gas gun.

That would be totally counterproductive, since the higher the molecular
weight of the gas, the slower the muzzle velocity of the gas gun will be.

And in any event, not even a multistage gas gun can accelerate projectiles
to 50 kps.


> I think the required x-ray (or was it gamma ray) heating for your Lithium
> deuteride may be generated by that hypervelocity plasma (on impact)
> trying to move outward in that magnetic field , radial fashion.

The function of the soft X-rays filling the hohlraum of a "conventional"
fusion weapon is to _UNIFORMLY COMPRESS_ the LiD via its radiation pressure
to enormously high densities, ~10 times that of lead, and comparable to the
densities in the core of the Sun --- =NOT= to "heat" the LiD !!! Unlike
magnetic confinement fusion, for inertial confinement fusion it is the
_DENSITY_, =NOT= the temperature, that is the critical factor in achieving
an efficient "burn."


You really should try doing do some research before you post. Most of
this stuff has been discussed for =DECADES= in the open literature !!!

You should also do some research into the physics of nuclear weapons.
Again, the qualitative aspects of how they work and even many of the
quantitative aspects have been available in the open literature for
a =LONG= time --- and they DON'T work the way you seem to think they do !!!


-- Gordon D. Pusch

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